Marine biologist Mark Read in Life on the Reef.
Mark Read is an optimist. As a marine biologist, he's fully aware of the many threats to the Great Barrier Reef. But he's also inspired by the people, like him, who live and work on it.

"My job is about identifying sensitive areas and making sure they are maintained for current and future generations," he said. "It's about working closely with the people who use the reef all the time - government, non-government, industry, traditional owners, the defence department - seeing whether the activities they are engaged in can be modified to actually make them more ecologically sustainable, while still providing a top-level product for their consumers.

"The interesting thing is that so many of the people that I would be talking to out there on the reef are already some of the best environmental stewards that we have. These are people that are constantly pushing the envelope to ensure that whatever they do allows them to make a living that minimises the impact on the reef. That's one of the lovely parts of my job that I get to rub shoulders with people like that who are just inspirational."

Read, who is manager of species conservation at the Great Barrier Reef Marine Parks Authority, is one of the characters you'll meet tonight in the ABC's spectacular documentary, Life on The Reef. He's forced to stay in an office in Townsville most of the week, but "any excuse to get out on the water, I'll take it or make it".

"I think we sometimes forget just what an amazing place the Great Barrier Reef is. You're talking about the largest living creature, or assemblage of creatures, on the earth. It stretches for 10,000 kilometres. You can see it from space. One of the things that's unique about the reef is the people who really feel passionately about it."

Read hopes the documentary will make Australians more aware of the threats, which he identifies as climate change through greenhouse gas emissions, unsustainable fishing practices, run-offs from the land, and the crown of thorns starfish.

"The starfish have been documented over the years as being one of the most significant contributors to the decline of the coral cover over the reef. There's a link between the success of the crown of thorns starfish and the amount of nutrients and sediments and run-off coming off the land."

What's his favourite place on the reef? "As soon as you mention the Barrier Reef, people think of coral, but for me I like the estuarine areas, the mangroves, because they're very diverse and they are places not a lot of people go to and value. I really like spending time there and going fishing."

Fishing? Doesn't that contribute to the stripping of resources? "Not at all - I'm not that good a fisherman. For me it's about being in the environment, so if I catch a feed, that's a bonus."